#include <iostream>
#include <string>
#include <unistd.h>
#include <cstdlib>
#include <sys/types.h>
#include <sys/wait.h>

using std::cout;
using std::endl;

int main()
{
    int fds[2] = {0};
    int n = pipe(fds);

    // cout << fds[0] << endl;
    // cout << fds[1] << endl;

    pid_t id = fork();
    if (id < 0)
    {
        std::cerr << "fork error" << std::endl;
        return 2;
    }
    else if (id == 0)
    {
        // 子进程
        close(fds[0]);
        int cnt = 0;
        int total = 0;
        while (true)
        {
            std::string message = "h";
            // message += std::to_string(getpid());
            // message += ",";
            // message += std::to_string(cnt);

            total += write(fds[1], message.c_str(), message.size());
            cnt++;
            std::cout << "total: " << total << std::endl;
            sleep(2);
            // break;
        }

        close(fds[1]);
    }
    else
    {
        // 父进程
        close(fds[1]);
        char buffer[1024];
        while (true)
        {
            ssize_t n = read(fds[0], buffer, 1024);
            if (n > 0)
            {
                buffer[n] = 0;
                cout << "child-father,message" << buffer << endl;
            }
            // else if (n == 0)
            // {
            //     // 如果写端关闭
            //     // 读端读完管道内部的数据，在读取的时候，
            //     // 就会读取到返回值0，表示对端关闭，也表示读到文件结尾
            //     std::cout << "n:" << n << std::endl;
            //     std::cout << "child quit ??? me too" << std::endl;
            //     break;
            // }
            // close(fds[0]);
            // break;
            std::cout << std::endl;
        }
        int status = 0;
        pid_t rid = waitpid(id, nullptr, 0);
        std::cout << "father wait child success: " << rid << " exit code: ";

        std::cout << "father wait child success: " << rid << " exit code: " << ((status << 8) & 0xFF) << ", exit sig: " << (status & 0x7F) << std::endl;
    }

    return 0;
}